Thermal management system of ship composite energy power system and control method thereof

Abstract

A thermal management system of a ship composite energy power system and a control method thereof are provided, including a thermal management circuit, which includes a seawater heat exchange circuit, an internal combustion engine thermal management circuit, a hydrogen fuel cell thermal management circuit, and a power battery and accessories thermal management circuit. It provides a thermal management control strategy for composite energy of internal combustion engine, fuel cell, and power battery; the various circuits can be independently adjusted; the heat dissipation effect is obvious, and the temperature of each cooling circuit can be better controlled; the energy utilization rate can be improved; the heat can be transferred to the other subsystems, and the heat dissipation area can be enlarged; and the fuel cell circuit can be elevated to the temperature by the heat exchanger and the electric heater, and it can reach the target working temperature more quickly.

What is claimed is: 
     
       1. A thermal management system of a ship composite energy power system, comprising a thermal management circuit, wherein the thermal management circuit comprises a seawater heat exchange circuit, an internal combustion engine thermal management circuit, a hydrogen fuel cell thermal management circuit, a power battery and accessories thermal management circuit;
 the seawater heat exchange circuit is configured to dissipate heat with the internal combustion engine thermal management circuit, the hydrogen fuel cell thermal management circuit, and the power battery and accessories thermal management circuit; the internal combustion engine thermal management circuit is configured to control the internal combustion engine to operate at a suitable temperature and provide heat for the hydrogen fuel cell thermal management circuit; the hydrogen fuel cell thermal management circuit is configured to maintain the hydrogen fuel cell at a suitable temperature, assist in cooling the internal combustion engine thermal management circuit, and increase the temperature of the power battery and accessories thermal management circuit; and the power battery and accessories thermal management circuit is configured to maintain the power battery and auxiliary components at a suitable operating temperature; 
 the seawater heat exchange circuit comprises a first heat exchanger, a second heat exchanger, a third heat exchanger, a seawater inlet, a seawater outlet, and pipelines connecting various components; and the seawater inlet, the first heat exchanger, the second heat exchanger, the third heat exchanger, and the seawater outlet are sequentially connected through the pipelines; 
 the internal combustion engine thermal management circuit comprises an internal combustion engine, the first heat exchanger, a fourth heat exchanger, a first water pump, a first expansion water tank, and a first electromagnetic three-way valve; the internal combustion engine, the first water pump, the first heat exchanger, the first electromagnetic three-way valve, the fourth heat exchanger, and the first expansion water tank form a closed loop through the pipelines, and the first electromagnetic three-way valve is connected to the first water pump through the pipelines; the first water pump is configured to drive coolant in the internal combustion engine thermal management circuit to flow, taking away heat generated during operation of the internal combustion engine; the first expansion water tank is configured to ensure timely discharge of air inside the internal combustion engine thermal management circuit; the first heat exchanger is configured to exchange heat between the internal combustion engine thermal management circuit and the seawater heat exchange circuit; the fourth heat exchanger configured to exchange heat between the internal combustion engine thermal management circuit and the hydrogen fuel cell thermal management circuit; and the first electromagnetic three-way valve is configured to adjust heat dissipation; 
 the hydrogen fuel cell thermal management circuit comprises a hydrogen fuel cell, the second heat exchanger, the fourth heat exchanger, a fifth heat exchanger, a second water pump, a second expansion water tank, an electric heater, and a second electromagnetic three-way valve; the hydrogen fuel cell, the second expansion water tank, the second heat exchanger, the fifth heat exchanger, the second electromagnetic three-way valve, and the second water pump form a closed loop through the pipelines; the hydrogen fuel cell, the second expansion water tank, the fourth heat exchanger, the electric heater, the second electromagnetic three-way valve, and the second water pump form another closed loop through the pipelines; the second water pump is configured to drive coolant in the hydrogen fuel cell thermal management circuit to flow, ensuring heat circulation and reducing the temperature difference between an inlet and an outlet of the hydrogen fuel cell; the second expansion water tank is configured to ensure timely discharge of air inside the hydrogen fuel cell thermal management circuit; the second heat exchanger is configured to exchange heat between the hydrogen fuel cell thermal management circuit and the seawater heat exchange circuit; the fourth heat exchanger is configured to exchange heat between the hydrogen fuel cell thermal management circuit and the internal combustion engine thermal management circuit; the electric heater is configured to increase temperature of coolant flowing through the electric heater; the fifth heat exchanger is configured to exchange heat between the hydrogen fuel cell thermal management circuit and the power battery and accessories thermal management circuit, reducing temperature of coolant flowing through the fifth heat exchanger in the hydrogen fuel cell thermal management circuit, and increasing temperature of coolant flowing through the fifth heat exchanger in the power battery and accessories thermal management circuit; and the second electromagnetic three-way valve is configured to regulate heat dissipation; 
 the power battery and accessories thermal management circuit comprises the power battery, a controller, the third heat exchanger, the fifth heat exchanger, a third water pump, a third expansion water tank, and a third electromagnetic three-way valve; the power battery, the controller, the third heat exchanger, the third electromagnetic three-way valve, and the third water pump form a closed loop through the pipelines; the power battery, the controller, the fifth heat exchanger, the third expansion water tank, the third electromagnetic three-way valve, and the third water pump form another closed loop through the pipelines; the third water pump is configured to drive coolant in the power battery and accessories thermal management circuit to flow, ensuring heat circulation; the third expansion water tank is configured to ensure to timely discharge of air inside the power battery and accessories thermal management circuit; the third heat exchanger is configured to exchange heat between the power battery and accessories thermal management circuit and the seawater heat exchange circuit, reducing temperature of coolant flowing through the third heat exchanger; the fifth heat exchanger is configured to exchange heat between the power battery and accessories thermal management circuit and the fuel cell thermal management circuit, increasing the temperature of the coolant flowing through the fifth heat exchanger; and the third electromagnetic three-way valve is configured to regulate heat dissipation. 
 
     
     
       2. A control method of a ship composite energy power system, using a thermal management system of the ship composite energy power system as claimed in  claim 1 , comprising the specific content is as follows:
 working modes of thermal management is divided into two situations: a cold-start and a normal mode; 
 the cold-start is divided into two modes: a normal temperature cold-start and a low temperature cold-start; 
 t0 is the boundary between the low temperature cold-start and the normal temperature cold-start, t1 is a lower limit of a working temperature range of the internal combustion engine, t4 is an upper limit of the working temperature range of the internal combustion engine, t2 is a lower limit of a working temperature range of the hydrogen fuel cell, t5 is an upper limit of the working temperature range of the hydrogen fuel cell, t3 is a lower limit of a working temperature range of the power battery, and t6 is an upper limit of the working temperature range of the power battery; 
 a low temperature cold-start control method: when ambient temperature is below t0, entering a low temperature cold-start cycle, first starting the internal combustion engine, and the first electromagnetic three-way valve has a small opening to minimize a flow rate through the first heat exchanger; the internal combustion engine thermal management circuit goes through a small cycle, comprising the circulation process that the coolant flows from the first water pump to the internal combustion engine and then to the first expansion water tank, then flows through the fourth heat exchanger, and then flows through the first electromagnetic three-way valve to return to the first water pump; increasing temperature of coolant flowing through the fourth heat exchanger until inlet temperature of the internal combustion engine reaches t1; gradually changing an opening of the first electromagnetic three-way valve to control the temperature of the internal combustion engine to work between t1 and t4; the second electromagnetic three-way valve in the hydrogen fuel cell thermal management circuit has a small opening to minimize a flow rate through the second heat exchanger; the hydrogen fuel cell thermal management circuit goes through a small cycle, comprising the circulation process that the coolant flows from the second water pump to the hydrogen fuel cell and then to the second expansion water tank, and then flows through the fourth heat exchanger and the electric heater, finally returns to the second water pump through the second electromagnetic three-way valve; the electric heater works, raising inlet temperature of the hydrogen fuel cell until the inlet temperature of the hydrogen fuel cell reaches t0, PTC (positive temperature coefficient) electric heater (positive temperature coefficient) electric heater stops working and the hydrogen fuel cell begins to start; when the inlet temperature reaches t2, gradually adjusting an opening of the second electromagnetic three-way valve to control the hydrogen fuel cell work at temperature between t2 and t5; the third electromagnetic three-way valve in the the power battery and accessories thermal management circuit has a small opening to minimize a flow rate through the third heat exchanger; the power battery and accessories thermal management circuit goes through a small cycle, comprising the circulation process that the coolant flows from the third water pump to the power battery and accessories, and then to the fifth heat exchanger, and then flows through the third expansion water tank and returns to the third water pump through the third electromagnetic three-way valve, until inlet temperature of the coolant reaches t0, the power battery begins to supply power to the ship composite energy power system; after the inlet temperature reaches t3, the opening of the third electromagnetic three-way valve is controlled to control the inlet temperature of coolant between t3 and t6; 
 a normal temperature cold-start method: when the ambient temperature is above t0, entering the normal temperature cold-start cycle; the power battery starts working first to increase the starting speed of the ship, starting the fuel cell and internal combustion engine at the same time; after the internal combustion engine is started, the internal combustion engine works together with the power battery to provide power for a forward movement of the ship, and the hydrogen fuel cell is in idle operation mode before the inlet temperature of the hydrogen fuel cell reaches t2; after the inlet temperature of the hydrogen fuel cell reaches t2, the thermal management system of the ship composite energy power system enters into a normal working mode, the first electromagnetic three-way valve in the internal combustion engine circuit has a small opening in the normal working mode, increasing the temperature of the coolant flowing through the fourth heat exchanger until the inlet temperature of the internal combustion engine reaches t1; the opening of the first electromagnetic three-way valve is gradually changed to control the internal combustion engine to work at the temperature between t1 and t4; the second electromagnetic three-way valve in the hydrogen fuel cell thermal management circuit has a small opening, and the circuit goes through a small cycle to increase the inlet temperature of the hydrogen fuel cell until the inlet temperature of the hydrogen fuel cell reaches t2; the opening of the second electromagnetic three-way valve is gradually adjusted to control the hydrogen fuel cell to work at the temperature between t2 and t5; the third electromagnetic three-way valve in the power battery and accessories thermal management circuit has a small opening, and the circuit goes through a small cycle until the inlet temperature of coolant reaches t3, controlling the opening of the third electromagnetic three-way valve to control the inlet temperature of the coolant between t3 and t6; 
 temperature control method under normal working mode: calculating an inlet target working temperature based on a current target output power; taking the target working temperature as a feed-forward value, and subtracting the feed-forward value from an actual inlet temperature to obtain an input of the controller; the output of the controller determines the openings of the first electromagnetic three-way valve, the second electromagnetic three-way valve, and the third electromagnetic three-way valve, making the actual temperature close to the target working temperature.